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New submitter Lasrick writes "Skip past the dry abstract to Jan Beyea's main article for a thorough exploration of what's wrong with current 'safe' levels of low-level radiation exposure. The Bulletin is just releasing its 'Radiation Issue,' which is available for free for two weeks. It explores how the NRC may be changing recommended safe dosages, and how the studies for prolonged exposure have, until recently, been based on one-time exposures (Hiroshima, etc.). New epidemiological studies on prolonged exposure (medical exposures, worker exposures, etc.) are more accurate and tell a different tale. This is a long article, but reads well." Here's the free, downloadable PDF version, too.

Ionizing radiation causes cancer. More ionizing radiation causes more cancer. There is no "safe dose", though there is a certain unavoidable dose. So we're all at risk of cancer if we live long enough.

Precisely - "low-level" at Sellafield in the UK used to mean "lower than the background level", and people still got hysterical about it. We need to stop with the wooly-language descriptions and simply use the established units, or units-above-background where applicable. Is low level gamma worse than high level alpha? Is holding a piece of uranium for 5 minutes more or less dangerous than sleeping 10ft away from it for a week? People have no idea, including most of the media, we need to throw out the "levels" model and actually educate people so they can understand the risks properly.

The problem with sieverts is that its never used to a large enough degree that people can recognize its size.A example of a almost universally known unit: Seconds. 3600 is a hour, 7200 is 2 as some might spot, and anything over that people have no idea about the amount of time it amounts to. If i say 22 680 seconds, people have no idea about what amount of time that is, beyond that its a lot of time.

The problem with sieverts is that its never used to a large enough degree that people can recognize its size.A example of a almost universally known unit: Seconds. 3600 is a hour, 7200 is 2 as some might spot, and anything over that people have no idea about the amount of time it amounts to. If i say 22 680 seconds, people have no idea about what amount of time that is, beyond that its a lot of time.

Ok, so your problem with sieverts is also a problem with seconds, and seconds are in every day usage.

By your estimation then, we are screwed, and can't possibly talk about levels of radiation, because people's eyes gloss over when we talk about long periods of time using an inappropriate unit of time measurement. You apparently see no way out of this problem, and you throw up your hands in despair, and walk off in resignation.

Exposure is always expressed in amounts over the background rate. So "Lower than background level" effectively means exposure to up to 2x the background level (background level + artificial); there's nothing illogical about being worried about it (though I wouldn't personally be concerned about a ~.0025 Sv per year exposure rate).

As for the rest of your comment, if you read the paper the summary links to, you'll see that all the evidence is pointing toward all exposure (presumably below radiation poisoning levels) carrying approximately the same relative risk. It doesn't matter high or low energy, it doesn't matter if you're exposed in 10 minutes or 10 years. Your total exposure level linearly maps to your risk of cancer (and, new information to me at least, heart attack and stroke).

This actually makes no sense though, well it does and doesn't. It does in the sense that the model is flawed as in the average lei person may not now that holding uranium for 5 minutes is less harmful than sleeping 10 ft away from it for a week. It doesn't in the sense that the average lei person doesn't really care. When in their lifetime are they going to be picking up uranium for 5 seconds much less 5 minutes, and if they are sleeping 10 ft away from it, I'd wager they don't know it.

We need to stop with the wooly-language descriptions and simply use the established units, or units-above-background where applicable. Is low level gamma worse than high level alpha? Is holding a piece of uranium for 5 minutes more or less dangerous than sleeping 10ft away from it for a week?

Unfortunately numbers are not that helpful on their own, the type of exposure matters a lot too. If you manage to get radioactive particles inside your body, particularly in your organs, then the risk is much higher. That is why there is so much more danger for children. Their bodies absorb more of this material are their organs grow, and they are naturally more prone to exposure to dust and dirt as they play.

Your best bet is to read a high-school level introduction. Concisely, there are three types of radiation from radioactive atoms, alpha, beta and gamma. Alpha is a He nucleus, two protons and two neutrons - it can do a huge amount of damage to living cells, but is easily stopped by, eg, a sheet of paper. Beta is a high speed electron, less damaging but will penetrate clothing etc. Gamma is nasty - it can travel through a reasonable thickness of lead and still do harm.

If we look at the Uranium example, it gives off alpha, so you'd probably be quite safe with it on the other side of the room. Handling it, on the other hand, is an easy way to accidentally ingest some, which would probably be more harmful because it's then inside the body (this goes for any ionizing radiation source). When you see people being showered off after radiation exposure it doesn't stop any harm thats already been done, just reduces the chances that they are still in contact with a source.

This all ignores the fact that Uranium decays into several other isotopes which give off their own idiosyncratic radiation in turn, and a bunch of other things.

Handling uranium is relatively safe, since the callouses in our hands and the outer most (dead) layers of skin easily block the alpha radiation. Ingesting it is far worse though, as you mention, though not foremost due to the alpha radiation, but due to uranium being a toxic metal. Wikipedia gives a good summary [wikipedia.org].

If we look at the Uranium example, it gives off alpha, so you'd probably be quite safe with it on the other side of the room. Handling it, on the other hand, is an easy way to accidentally ingest some, which would probably be more harmful because it's then inside the body (this goes for any ionizing radiation source). When you see people being showered off after radiation exposure it doesn't stop any harm thats already been done, just reduces the chances that they are still in contact with a source.

And that is why people are so worried about the area around Fukushima. I see a lot of posts on Slashdot about how the radiation levels are so low they pose no risk, but that simply isn't true if a source of ionising radiation gets inside the body. Contaminated soil, food, water and dust are all problems that are costing billions to fix, but the work has to be done.

You seem to have not read the abstract, the whole point of which is at ultra unrealistically low levels, practically homeopathic low levels, the mechanism, the cause/effect seems to not make much sense or is under debate, both real scientific debate and crackpot astroturfing debate. But the article points out that at any realistic dosage level there is not much debate by anybody. So the article pragmatically suggests to only apply real world numbers to real world exposures and ignore the whole topic of unattainably asymptotic low levels. The article argument is the opposite of yours in some ways.

An example of a realistic question at the ultra-low end is, looking at how naturally radioactive some of our high potassium food is, you'd think we'd evolve a way to pee the bad stuff away. Presumably people evolved in granitic-source / volcanic-source soil would be better at it than people evolved in sedimentary-source soil. Another realistic area of cancer research is proving the presence or absence of two-step or catalysts of cancer. Your body is pretty good at dealing with mutant cells, except when it fails and then you die of cancer, whoops. So figuring out why your body fails to kill cancer cells is in many ways more important than trying to figure out how to reduce the number of cells caused by radiation because even if you zero that, you're still going to have random biochemical accidents. Its an interesting theoretical area of research but the article points out for normal human beings its at a level that doesn't matter.

Ah I'm not talking about cancer being like evolution, talking about evolution if you live in a niche of really high radioactive potassium consumption from eating bananas all the time, after a bazillion generations you'd expect the survivors to be better than the average human about excreting radioactive or otherwise K and/or getting by with as little of that nasty stuff inside them as possible, despite it being a big part of their diet.

Ah I'm not talking about cancer being like evolution, talking about evolution if you live in a niche of really high radioactive potassium consumption from eating bananas all the time, after a bazillion generations you'd expect the survivors to be better than the average human about excreting radioactive or otherwise K and/or getting by with as little of that nasty stuff inside them as possible, despite it being a big part of their diet.

Its also not clear just how long this adaptation takes.Every once in a while an article you find about animals in the Chernobyl exclusion zone suggests that the supposed ill effects are simply not appearing at anywhere near the rates expected or encountered in laboratory experiments.

He and his team are studying the mice to understand their resistance to radioactivity. They've found sensitivity to ionization, which results in certain tumors, and some of this passes down through the genes. But they're also finding heritable radiation resistance—which could perhaps be beneficial to humans someday.

There are other, mostly earlier, studies showing significant bug population decline around 2009.

Not necessarily. Until relatively recently the average life expectancy was less than 35, much lower in pre-agricultural societies. Since radiation can take decades to cause cancer most of the people affected may have already died of other causes, so there is no evolutionary advantage to being resistant.

Of course. The question is, how much more cancer is caused by a given dose of radiation?

Unfortunately, this is a question that the paper in question does not answer, because it completely neglects to mention actual numbers. (The pretty colored graphs have units of "excess relative risk." How do you convert that to deaths? You can't. What are the units-- per year? Per lifetime? they don't say. Relative to what? They don't say.) I'd like to see a number, like "excess cancers per year per sievert of exposure," but they don't give one. They compare different studies, but never discuss whether the differences are statistically significant.

There is no "safe dose", though there is a certain unavoidable dose.

That is a question. That is what is known as the "linear no threshold" model-- but although these authors assert the validity of that model, you can't tell it from the data they show. Figure 1 shows too much scatter below 0.3 Sv to give much information about thresholds, and Figure 2 sure looks like it would be well fit by a threshold model.

That is, if cosmic radiation were in fact the main location-dependent factor that caused cancer.

But since cosmic radiation dose is something on the order of 0.5 millisievert per year, it's probably not significant enough to see the signal over the noise, assuming that there are other sources of cancer.

Of course. The question is, how much more cancer is caused by a given dose of radiation?

Unfortunately, this is a question that the paper in question does not answer, because it completely neglects to mention actual numbers. (The pretty colored graphs have units of "excess relative risk." How do you convert that to deaths? You can't. What are the units-- per year? Per lifetime? they don't say. Relative to what? They don't say.) I'd like to see a number, like "excess cancers per year per sievert of exposure," but they don't give one. They compare different studies, but never discuss whether the differences are statistically significant.

FIG. 3. Solid cancer dose–response function. The thick solid line isthe fitted linear gender-averaged excess relative risk (ERR) dose responseat age 70 after exposure at age 30 based on data in the 0- to 2-Gy doserange. The points are non-parametric estimates of the ERR in dose categories.The thick dashed line is a nonparametric smooth of the categoryspecificestimates and the thin dashed lines are one standard error aboveand below this smooth.

Or in other words: "Oxygen causes seizures. More oxygen causes more seizures. There is no "safe dose", though there is a certain unavoidable dose. So we're all at risk of seizures if we live long enough."

Makes perfect sense to me. After all, all biological systems respond to all environmental effects not just monotonically, but linearly! For example, if you put a person in a pneumatic press you will crush them to death. It follows from this that you should never, ever give a person a hug. After all, th

Ionizing radiation causes cancer. More ionizing radiation causes more cancer. There is no "safe dose", though there is a certain unavoidable dose. So we're all at risk of cancer if we live long enough.

The standard/. car analogy breaks down in that running my car engine up to 80% of redline RPM for a half hour a day is a pretty stupid idea that will only wear it out faster. Yet daily aerobic exercise seems to be a brilliant idea for long term cardiovascular health.

You can also have hilarious fun making vaccine analogies. "You mean, you'd intentionally inject small amounts of possibly fatal microbes into a healthy body? Madness I tell you! Madness!" Sadly there are highly educated actresses and pr0n models who pretty much use this argument when providing their valuable medical advice, along with the usual folks doing the FUD-for-profit thing.

I've not read the paper yet, but it makes sense from a certain standpoint.

A single high dose causes massive widespread damge. Cells die, immune system ramps up, and rapairs get underway. A cell that might have become cancer dies in a scab, or fall off, or is cleaned up in some way amoung the countless others. Low level raditon damages just a tiny bit. Not enough to cause a reaction or massive cell death. This gives each cell that could become cancerous a better chance to live and become a problem.

some research (no links... i found it while wiki walking) indicates that lower exposures over longer times reduce the risk somewhat, which seems in stark contrast to TFA. sort of like reciprocity failure on photographic film, or the thresholded linear thing.

There is no threshold below which radiation is 'safe'. There is a threshold below which is become statistically indistinguishable from random events, but that is not the same thing. We've known even "low" levels of radiation can be dangerous -- look at the cancer clusters showing up in TSA screeners. The scanners were declared 'absolutely safe' and had a 'low' level of radiation. There is a long history in the medical field of radiology where equipment, engineering, or our understanding of underlying principles failed and led to death or serious injury. The fact is, there is no such thing as "safe". That doesn't mean don't use the equipment -- it's often the only way to get the information needed (note: full body scanners NOT included, there are alternatives which provide the same information). But it does mean use the least amount of radiation necessary, only use it when necessary, and carefully track a person's exposure -- time, dosage, etc., to identify trends.

Radiation is a daily reality in our lives. Go outside, look up. There it is; the biggest source of radiation in your life (most likely). We can't avoid it... but we can limit it.

There might be a level at which radiation is beneficial. This is called hormesis [wikipedia.org]

From Wikipedia

Hormesis (from Greek hórmsis...) is the term for generally favorable biological responses to low exposures to toxins and other stressors. A pollutant or toxin showing hormesis thus has the opposite effect in small doses as in large doses

The concept is vigorously debated, but has been shown to work in some animal experiments. In humans, small doses of alcohol, a toxin, seems to improve heart health.

Humans, as all life, have evolved under low level background radiation. We may be adapted to it.

In humans, small doses of alcohol, a toxin, seems to improve heart health.

alcohol is a liver toxin, just like fructose (insert std flamewar about fructose being a toxin, complete with youtube links).

You can do the pubmed thing but as a crude first approximation alcohol only screws up muscle (like heart) as a secondary effect by first screwing up your digestive system and blood chemistry and nervous system. Muscle itself doesn't met messed up by alcohol until its practically pickled. Notice the ratio in alcoholic deaths of liver vs stomach/intestine cancer (stomach is muscle, mo

Actually there are a number of studies out that quite clearly demonstrate that alcohol in moderate doses is good for you, in the specific sense that moderate drinkers experience less morbidity and mortality from all causes than either teetotalers or full-blown alcoholics. The "moderate" range appears to be 1-3 drinks a day, depending on your body mass and personal chemistry, but curiously, the Mediterranean study showed that at least elderly drinkers outlive nondrinkers (on average) completely blind to the

Sounds like statistical studies. I was thinking of reaction mechanisms. Mystifies me how alcohol could do any good to a liver from a reaction mechanism basis. I could see from a statistical study where "getting a nice buzz" might lower stress levels, lowering blood pressure, increasing lifetime. However, you'd get the same cardio relaxation effects from a nice mild tranq pill without the higher liver toxicity of alcohol, or just tell them to meditate more...

I think that you aren't giving the possibility of positive reaction mechanisms enough credit. Humans have co-evolved with alcohol for at least 6 to 10 thousand years. Over the overwhelming bulk of that time, if you did not drink alcohol your life was ugly, nasty, brutish, parasite ridden, and short. There is an interesting program on Netflix you might want to watch entitled "How Beer Saved the World" -- tongue in cheek but not really. It's really only been safe to drink the water for less than 100 years, in some levels of wealthy and scientifically advanced society, in countries where it is safe to drink the water, which isn't most countries even now, presuming you think drinking halogenated water is "safe". I grew up in India, and used to drink beer on the road when we travelled at age seven or eight, because it was one of precisely three safe options once you ran out of boiled water or iodine tablets. Tea (boiled water, no milk). Coca Cola -- because even if you dropped a cockroach into Coke as it was bottled, you'd just eat/drink down an acid-pickled cockroach and be perfectly fine. And beer. Golden Eagle beer, to be specific, is the earliest beer I can recall tasting. Back then they didn't have bottled water for sale.

For the most part the body metabolizes alcohol in moderation harmlessly. It isn't particularly directly toxic to the liver (although fermentation adjucts may be), it's just that the liver tends to get fat, just as it does (as you observe) if you eat enough carbs or the wrong sugars and have metabolic syndrome or type 2 diabetes. Alcohol acts as a mild blood thinner -- not unlike aspirin, but not as strong -- and hence may be directly beneficial at moderate levels for precisely the same reasons that aspirin is (and aspirin has its own toxicity and side effect issues, although they are rare in adults). As you note, it is a fairly harmless relaxant. The Mayo clinic lists it -- with warnings -- as being "possibly good for" reducing risk of heart disease, dying of a heart attack, risk of strokes (especially ischemic strokes), lowers your risk of gallstones (my grandmother was prescribed one beer a day, which she drank very religiously and dutifully being the wife of a Methodist Minister who did not hold with drinking, for this very reason, way back in the 1960s, as an alternative to taking a wad of horrendous-sized pills), and diabetes. Their guideline is one drink for women and two for men, but of course this depends on body size. Women are at greater risk then men (relative to any benefits) because of their higher risk of breast cancer, BTW.

As for statistical studies, they are how one proves that prayer and astrology do not work. You got that one backwards, thought I'd help you out. You're thinking of "anecdotal evidence", not double blind placebo controlled statistical studies. Even in physics (where I'm a physicist) correlation may not be causality but it is often all one has until one maybe eventually formulates a theory that might explain it, and that theory has as its ultimate foundation what? Evidence in the form of statistical correlation, of course. What else is there?

With that said, given the mass of Bayesian priors (a.k.a. "laws of nature" and the like) we have arrived at that are reasonably statistically sound, I totally agree that one should look for reaction mechanisms and explanations, but don't forget what they are explaining -- the statistically sound results obtained from the data. On a really good day, you come up with both the mechanism and the data and they are consistent and the mechanism predicts other things as well and then you get your Nobel prize and everything. Other days you are up against multifactorial effects and sparse data and trying to make sound inferences of cause is, well, "challenging" even though the statistical correspondence itself may be as sound as you like.

These days I brew my own beer and ale, all carbonated naturally in the bottle. Nothing but barley, hops, yeast and water, and because each bottle is unfiltered and contains live yeast, I get a dose of B-complex vitamins, and traces of chromium and selenium in every glass. I control the alcohol content and the fractional ratio of dextrose (fermented to alcohol) and dextrins (complex sugars the yeast do not eat and which contribute body and residual sweetness to the final beer). Hops contain flavonoids (pi

Linked paper talks about hormesis, specifically about how it's a largely debunked theory that isn't taken seriously by anyone in the field any more. In fact, there's research that shows low level radiation being more harmful (in a relative, risk vs Sv exposed way) than less.

Yes, hormesis has been shown in many many low level radiation studies. When you get to higher levels, things look pretty linear but at lower levels you generally see a standard dose-response type of curve.

I haven't had time to read the article fully yet, but the research I have seen seems to contradict the summary of the article. The regulatory agencies have been trying to suppress studies and research on radiation hormesis for quite some time, and have misrepresented scientific findings in many ways.

There is no threshold below which radiation is 'safe'. There is a threshold below which is become statistically indistinguishable from random events, but that is not the same thing. We've known even "low" levels of radiation can be dangerous -- look at the cancer clusters showing up in TSA screeners.

Unfortunately, what you say is at best inconclusive, but at worst wrong. Google "hormesis".Studies "including for example the respected "Iowa Radon Lung Cancer Study" of Field et al. (2000), which also used sophisticated radon exposure dosimetry....argue that radon exposure is negatively correlated with the tendency to smoke and environmental studies need to accurately control for this; people living in urban areas where smoking rates are higher usually have lower levels of radon exposure due the increased prevalence of multi-story dwellings".http://en.wikipedia.org/wiki/Radiation_hormesis [wikipedia.org]

I know that hormesis sounds like a crackpot theory along with holistic super-diluted medicinal honey therapy, but some of the greatest minds in Medical Physics believe it exists. It is basically the hypothesis that low levels of additional radiation can actually make you healthier than no additional radiation at all (including daily dosage of cosmic rays). Hence the quote about high background radon studies and inverse correlations with health outcomes.

One of the main mechanisms that is thought to possibly explain it is that while the additional radiation exposure is not enough to cause significant DNA damage, it still activates certain dormant mechanisms for DNA repair, resulting in a healthier-than-average individual.

So in short, there is at least very suggestive evidence for a "safe" (and even moreso than safe) level of radiation.

Quoting results from literature research,[6][7] they furthermore claim that approximately 40% of laboratory studies on cell cultures and animals indicate some degree of chemical or radiobiological hormesis, and state:

"...its existence in the laboratory is beyond question and its mechanism of action appears well understood."

They go on to outline a growing body of research that illustrates that the human body is not a passive accumulator of radiation damage but it actively repairs the damage caused via a number of different processes

Once again, yes even in the wikipedia "article" itself it is debated, but that's the point of error-bars in science.

I know that hormesis sounds like a crackpot theory along with holistic super-diluted medicinal honey therapy, but some of the greatest minds in Medical Physics believe it exists.

Extraordinary claims demand extraordinary evidence. Wikipedia is not evidence of any variety. It is commonly held, and backed by numerous studies, that ionizing radiation is harmful. non-ionizing radiation may be harmful, in cases where it causes heating of the tissue (especially eyes), or electrical discharge. Hearing that the "greatest minds" in medicine believe something is disappointing; In their field, I would hope they don't practice medicine based on belief... I would hope they do it based on facts,

I linked wikipedia because it's not behind a paywall like the citations to scientific papers it references are. And by "believe", I mean that the studies in question have large error bars associated with them due to the difficulty of controlling for so many variables, but that the mean trend motivates hormesis.

Given that there are papers for and against many topics similar to this in the scientific community, it is as much a statement as whether certain scientists either "believe" in global warming or not.

Unfortunately, what you say is at best inconclusive, but at worst wrong. Google "hormesis".

know that hormesis sounds like a crackpot theory along with holistic super-diluted medicinal honey therapy, but some of the greatest minds in Medical Physics believe it exists. It is basically the hypothesis that low levels of additional radiation can actually make you healthier than no additional radiation at all (including daily dosage of cosmic rays). Hence the quote about high background radon studies and inverse correlations with health outcomes.

Hormesis is irrelevent. The dosages that matter for medical, nuclear and public safety applications are well above the threshold where statistically significant evidence of any "benefit" can be found.

At low levels the signal you think you hear is the noise floor. We don't have necessary sample sizes in any practical study to see anything with meaningful certainty...not when 1/5th of us will die of cancer anyway. Having slept through university statistics courses each interest defaults to seeing what they

Demonstration of a quasi-threshold would be unlikely to assuage those who abhor radiation-producing technology on existential grounds, but it might eventually affect regulations and overall opinion. The radiation hormesis theory—that some radiation is beneficial—would provide more comfort, if it could be demonstrated. The best evidence for this concept in humans can be found in national data on home radon measurements and lung cancer rates at the county level. However, the reliance on cancer data aggregated to the county level has been roundly criticized by epidemiologists (Lubin, 2002). Results from more sophisticated epidemiologic studies of the same association do show the expected dose response when individual cancers are matched to dose (Darby et al., 2005; Krewski et al., 2006).

Though it still is a pet topic of enterprising journalists, the radiation hormesis theory is no longer of much interest to researchers. The BEIR VII report, published in 2006, discounted the concept; the French Academy of Sciences took it more seriously, while discounting other evidence that suggests the response might be supralinear at low doses.

Given the increase in radiation from medical diagnostics and the interest in protracted exposure, the possible existence of a threshold or hormetic effect for public policy appears to be a moot issue for developed countries when it comes to future exposures. Even if the level of medical diagnostic exposures does not increase in the future, over the course of 40 years most people in developed countries will receive an average of 0.1 Sv from medical procedures, alone. With this in mind as a dose starting point for millions of people, it is fair to say that any exposure to radioactive elements from a nuclear accident or a dirty bomb would definitely contribute to their delayed cancer risk.

That was pretty much the point of TFA. The most important factoid that comes from TFA is that the previously considered 'safe' value of 0.1 Sv DOESN'T drop down in the noise - there are excess cancers that can be discerned in published data at that level AND that the average medical radiation burden in developed countries is approaching that 0.1 Sv level.

Therefore, the combination of business as usual for medical radiation AND increased man made exposure from reactor leaks, bombs, spills and other detritus

Therefore, the combination of business as usual for medical radiation AND increased man made exposure from reactor leaks, bombs, spills and other detritus of the nuclear power industry would be additive above baseline. You might have what is thought to be a 'small' spill that turns out to have larger medical consequences than previously thought.

Presumably, coal power would have a few more deaths to add to its thousands and thousands of calculated deaths then, since a coal power plant is a greater source of

Seriously, the inflated risk estimates of the no-threshold model are a far greater threat to public safety than even those inflated risks themselves. There is any amount of evidence, as well as theoretical backing from our understanding of biology, that the biological effects of radiation are non-linear.

To take a trivial example: if it were otherwise, Q would always be 1. Since it isn't, radiation effects are non-linear. That's at the high end, but once you admit that it's possible the mantra "ther

Finally, why does the summary identify the source as "the Bulletin" rather than spelling out the full name, and why is anyone reading what purports to be a scientific report from a purely political anti-nuclear lobbying organization? It's like getting your information on birth control from "Conservative Catholic Christians for Reproductive Oppression."

I don't know where you're getting your info, but The Bulletin is actually a rather neutral publication. For the most part, the articles tend to be in favour of civil nuclear power, assuming that proper safeguards are in place etc... They also do a good job of presenting multiple sides of many issues, giving equal space to each of the arguments.

For example, when discussing Iran's nuclear ambitions, they began with a well researched article on what Iran's current capabilities are, how much weapons grade mate

The biggest source of ionizing radiation , is the background radiation (from a combo of the ground/environment (granite is different to say , chalk ground), sleeping near somebody, what you eat, the own atoms in your body which decay....). In the sky, except the UVA/UVB which should be pretty resonnable, it is mostly non ionizing UV,

The biggest source of ionizing radiation , is the background radiation (from a combo of the ground/environment (granite is different to say , chalk ground), sleeping near somebody, what you eat, the own atoms in your body which decay, medicine xray etc...). In the sky, except the UVA/UVB which should be pretty resonnable, it is mostly non ionizing EM.

From what I understand, this is not absolutely definitive, but cancer researchers at Lawrence Berkeley Lab published a paper [lbl.gov] where they used imaging of cellular responses to radiation damage to show that at low levels, it appears that cells repair DNA damage due to radiation very effectively.

Model fits, both parametric and nonparametric, to the atomic-bomb data support a linear no-threshold model, below 0.1 Sv.

OK so the data implies there is no safe minimum dose based on models derived from numerology and graphs and experience.

On the basis of biologic arguments, the scientific establishment in the United States and many other countries accepts this dose-model down to zero-dose, but there is spirited dissent.

But that doesn't seem to make biochemical sense. (eventually you end up in the radiation equivalent of homeopathy)

a sizeable percentage of this population will receive cumulative doses from the medical profession in excess of 0.1 Sv, making talk of a threshold or other sublinear response below that dose moot for future releases from nuclear facilities or a dirty bomb.

"moot" in science-speak means it doesn't matter. Its not a 4chan reference.

The risks from both medical diagnostic doses and nuclear accident doses can be computed using the linear dose-response model, with uncertainties assigned below 0.1 Sv in a way that captures alternative scientific hypotheses.

A big F you to both the cranks and the real biochemical / biophysical scientists, because no civilized human can go thru life below 0.1 Sv, you can rock on with your h

It's pretty well established that exposure levels are given in units above the background. This isn't new. If you were taught how to read a geiger counter in high school the first thing they should have taught you was how to zero it out so the background levels (which are different from place to place) didn't affect your measurements. So no, no one is going to go through life with less than.1Sv, not if they make it to 40 anyway, but most people who don't work in radiation exposing occupations and don't

But that doesn't seem to make biochemical sense. (eventually you end up in the radiation equivalent of homeopathy)

I don't think that argument applies here. Remember that we're talking about a probabilistic process here - people exposed to radiation have an increased risk of getting cancer that's hypothesised to be linearly proportional to their level of radation exposure. Even though radiation is quantized, if someone's been exposed to radiation levels so low that it's incredibly unlikely their body actually absorbed a single quanta of radiation their increased risk of cancer is roughly (probability of cancer from one

or in essence its like arguing that running your heart during aerobic exercise helps it age better, or vaccinating yourself by injecting dangerous microbes paradoxically reduces your odds of infectious death. Also you can have fun with a more engineering example like work hardening... who could guess that whacking softened copper with a hammer actually makes it stronger instead of just turning it to mush?

The homeopathy comment was more a measurement, ridiculous biochemically irrelevant concentration, rathe

"Thus, pressure to update regulations may build, as awareness grows of the five-to-tenfold disparity between the risk estimates per unit dose recommended by scientists today and the older values still used by regulators in cost–benefit calculations for determining allowable doses."

Do note that the "Bulletin of the Atomic Scientists" is a generally an anti-nuclear, scare-mongering publication. These are the people whose count-down to nuclear disaster has been just a few minutes before midnight for decades. Whatever they publish should be viewed with this in mind.

Scanning RFTA, in the end, it says basically nothing at all. They did no studies themselves, but just looked around at ones already done. The key points seem to be:

The same total exposure in the form of long-term exposure may be slightly (20%) more dangerous than the same dosage in a short, high-intensity form.

They desperately search for something to say about low-level, long-term exposure. They spend pages talking about the competing theories, from "Supralinear response" (really dangerous) to "Adaptive response" (a little radiation is healthy). In the end, they find no convincing evidence one way or the other, because the uncertainty bounds at such low levels include essentially all possibilities.

Based on this lack of evidence, they conclude that low levels of radiation are really dangerous, and that all Western populations are "primed for radiation-induced, delayed cancers from releases from nuclear reactors".

Do note that the "Bulletin of the Atomic Scientists" is a generally an anti-nuclear, scare-mongering publication

Utter nonsense. I remember perusing the print version of the Bulleting in my college library a few years ago, and it was anything but a knee-jerk, "scare-mongering" publication on nuclear issues. The articles were extremely informed and detailed.

There are two great articles that spring to mind. One was regarding a project run by the US government regarding how difficult it would be for countries without nuclear weapons to develop one. To test this, they found a physicist who had just gotten his PhD, making sure he that he wasn't someone with two much particular knowledge on nuclear physics. By using research from publicly-available sources he was able to eventually come up with a working design for a nuclear weapon. Just to be thorough he even designed a more complicated implosion design rather than a the simpler bullet design. The point of the article was that the difficult part for a country aspiring to create a nuclear arsenal is accumulating the proper uranium or plutonium. Creating the bomb is relatively simple.

The other article examined whether using depleted uranium for ammunition had lasting effects because of radioactivity. If I recall correctly, the radioactive aspect was not a concern. However, uranium can be poisonous without any consideration of its (limited) radioactivity. Since DU rounds piercing armor can cause the outer shell of them to vaporize, this could be a problem.

The Bulletin's conclusion was not obvious. Judging them just because of the Doomsday Clock is rash.

The point of the article was that the difficult part for a country aspiring to create a nuclear arsenal is accumulating the proper uranium or plutonium.

In other words, they rediscovered something that any professional or serious amateur in the field has known for decades.

The other article examined whether using depleted uranium for ammunition had lasting effects because of radioactivity. If I recall correctly, the radioactive aspect was not a concern. However, uranium can be poisonous without any co

In other words, they rediscovered something that any professional or serious amateur in the field has known for decades.

Umm. The Bulletin is not, nor does not pretend to be, a scientific journal. Many serious amateurs or all professionals would not use it as a source for the latest information in nuclear science. And whether the conclusion of the article is known by the reader or not is completely irrelevant. The story behind it would definitely be of interest to a serious amateur or professional.

The conclusion regarding depleted uranium ammunition may be obvious to you, but I remember the mainstream media of the time had a lot of knee-jerk scare-stories regarding the harmful effects from "all that radiation". Since the Bulletin had a more informed and balanced article on the topic than other sources at the time, this means that the OP's assessment of it as "scare-mongering" in regards to all things nuclear (and your defense of him) is wrong.

But when you're not completely missing the point I'm sure you can come up with a post with more substance than insults.

Just to clarify, when I said that "The Bulletin's conclusion was not obvious," I was talking about the conclusion of the original Slashdot topic (implied through bias). Not the conclusion of the two example articles I brought up.

By using research from publicly-available sources he was able to eventually come up with a working design for a nuclear weapon.

Where did they detonate it? If they didn't detonate it, how did they know it was a working design?

The BAS is a purely political organization pursuing a purely political goal. There are virtually no nuclear physicists involved in it because they don't do science: they are a lobbying organization.

That they can mislead someone who doesn't know anything about nuclear engineering into thinking that they do have some non-political agenda is unsurprising. Those of us who have PhDs in the subject and have worke

>>Utter nonsense. I remember perusing the print version of the Bulleting in my college library a few years ago, and it was anything but a knee-jerk, "scare-mongering" publication on nuclear issues

From the article: "Over the decades, as new excess cancershave emerged in the atomic-bombcohort at lower and lower doses, thenumber that defines Ã'low doseÃ" hasshrunk fivefold to its current value of0.1 Sv. At the same time, the estimatedrisk has risen tenfold since 1980;8 thus,it is of little surp

Do note that the "Bulletin of the Atomic Scientists" is a generally an anti-nuclear, scare-mongering publication. These are the people whose count-down to nuclear disaster has been just a few minutes before midnight for decades. Whatever they publish should be viewed with this in mind.

As a strong supporter of nuclear power I feel this attitude is exactly what makes it so easy to scare up opposition to nuclear power. That article was extremely well written and researched. IMO it presented a fairly balanced view of the existing studies and the overall challenges to new research and regulation. Yes their are concerns about low and protracted doses, and yes the industry has tried to downplay and bury that research. Just like the "green power" industry doesn't want anyone to look at the lifecycle costs on those PV cells and LiPo batteries.

The only way to stop fear mongering and get new power plants is with open and honest research - not making attacks on an article that tries to present the facts.

You have misinterpreted their conclusion. By "primed" they mean that all Western populations have enough exposure already from medical sources that everyone is above any "threshold" for zero-danger. They are just saying there is no reason to quest for this threshold and we should just get on with applying models that don't assume that there is such a magic threshold.

You could always find a Fox News article on the joys of chronic radiation exposure to fair and balance us. Post it to the Firehose.

Yes, the Bulletin on Atomic Scientists is anti nuclear but I'd hardly call them 'rabid'. You're not going to find a neutral point of view in this debate (and the article discusses this with a distinct slant), but it is still worth a read rather than an automatic dismissal.

1. They claim that LNT applies to prolonged exposure, and that the risks are actually higher than the single exposure data from Hiroshima. Examine Figure 2 in the PDF report and you'll see that while the data is within 1 sigma of LNT for the range of exposures shown, it actually appears to follow a quadratic curve, with lower ERR up to 0.25-0.3Gy, 2.5x-3x the "low-level" dose, then the risk is higher than LNT with higher cumulative exposure. From that chart, prolonged exposure to low-level (cumulative) is i

TFA is from the Bulletin of the Atomic Scientists, which is well known for its misleading literature and leftish bias.

Furthermore, consider that they're talking about dosages of 0.1 Sievert or more, which is still pretty high, given that the average US background radiation is about 0.003 Sievert/year. With the high scale they're considering, it would be impossible to detect the existence of hormesis. From what I've read, there is an optimum level of radiation, in the range of 0.005 to 0.010 Sievert/year.

The Beyea paper discusses human epidemiology. This is a completely fruitless endeavor. People have been trying for 60 years to determine the human body's response to low levels of ionization, and they've failed competely. The reasons for the failure are simple. Scientists can't do controlled experiments with human subjects, and scientists can't knowingly subject human subjects to harm.

Since you can't do good science with human test subjects, the obvious alternative is to use animals. Animal studies have bee

Here, I'll make you feel better. Barium is used as a contrast agent. It blocks the xray so that it creates a shadow where the barium is located (like in your gut). It's not radioactive in and of itself.

I can remember they use low level barium in hospitals for all kinds of scans. If even a low level already is unsafe, how many more have been affected by these low levels?

The risk, that are minimal, are considerably less than the risk that the physician might give a misdiagnosis if you don't have the procedure. I used to work administering the test that required the use of barium. I was a x-ray tech (I don't work in healthcare anymore), and I know for a fact that the overwelming majority of the barium that patients injest, or receives retrograde (if you don't know you don't want to find out), is passed out of the body after a couple of bowel movements. The actual x-ray i